The goals of this research are to increase the functional use and long- term outcome of patients with total hip replacement and hip revision. This study is important due to the necessity of using whole bone segmental allografts to replace proximal femurs that have become deficient in bone stock secondary to menopause, disuse, multiple revision arthroplasties, or that have tumor infiltration. The problem lies in the fact that functional impairment due to inadequate or failed muscle reattachment to the allograft commonly occurs. The working hypothesis for this investigation is that there are specific long-term time-related changes that occur in functional weight-bearing, densitometry, histology, and mechanical characteristics during the incorporation of the allograft tendon and bone following proximal femoral reconstruction that will allow selection of the optimal technique for this reconstruction. Using a canine model, three methods of gluteal attachment to proximal femoral allografts will be compared: (a) a host tendon to allograft tendon attachment using horizontal mattress sutures, (b)a host bone to allograft bone attachment using a cable grip system, and (3) a host bone bicortical half-shell wrapped around the allograft bone without disruption of the host tendon-bone interface. The prosthesis will be cemented to a frozen allograft and this composite cemented to the distal femur after an excision of the proximal 25% of the femur. The animals will be evaluated bimonthly with radiography, densitometry, and functional weight-bearing and at 9 (24 dogs) and 18 (24 dogs) months with histology and mechanical testing following humane euthanasia.